This document describes a project that developed software to dynamically scale mobile device backlight levels for streaming video applications. The software analyzes video content and adjusts the backlight to reduce energy consumption without compromising user experience. It was tested on an HTC Desire phone browsing YouTube, saving 18-31% in backlight energy. Potential business models are discussed, such as video providers embedding backlight scaling data in streams or energy service companies licensing the backlight adjustment technology. The goal is to address the major challenge of high energy consumption from increasing mobile video usage.

1. 2011電信創新應用大賽
行動應用社會組
行動多媒體串流
之省電應用軟體
隊伍名稱：EMCLAB@CITI
參賽單位：中央研究院 資訊科技創新研究中心
參賽者 ：謝承剛、林均翰、鄭志川、修丕承

2. Motivation
• Mobile applications and
services are having a
profound effect on people's
lifestyles.
• The energy consumption of
mobile devices is a major
challenge in sustaining the
applications and services.
• Cisco Forecast: Video
streams will account for 66%
of mobile data traffic by
2014.
2

3. Dynamic Backlight Scaling
• The screen backlight consumes
most of the energy for mobile
streaming applications.
• Dynamic backlight scaling is
deemed a promising technical
solution. Power distribution on HTC Desire when
• When to dim the backlight to browsing videos on YouTube
which level?
• Video distortion
• Hardware/software limitation
• User perception
• Etc. 3
• Our IEEE/ACM ISLPED’11
Dynamic Backlight Scaling
paper has the answer!

4. Android Software
• Without changing their user
preferences
• Display with YouTube
• Display with our software
• Functionality
• Turn on/off backlight scaling
• Show/hide backlight scaling
• Compute energy saved in joule
and percentage
• Pause, fast forward/backward 4

5. Demonstration – HTC Desire
Approach validation
Performance evaluation
5

6. Case Studies
Case studies
Experimental
results
6

7. Possible Scenario I:
Video Content Provider
Video Stream
Streaming Server
Mobile Device
• Backlight scaling information embedded in videos
• Expected Profits
• Less energy consumption for watching the same video
• More attractive to mobile customers than other competitors 7

8. Possible Scenario II:
Energy-Saving Service Provider
Video Stream
Streaming Server
Backlight File
Mobile Device Backlight Server
• Backlight scaling information provided with videos
• Expected Profits
• 1million users x 30 dollars/month = 30 million dollars/month 8
• Facility rental + maintenance cost ≈ 2 million dollars/month
• Net profit ≈ 28 million dollars/month

9. Conclusion
• Mobile users are addicted to media applications, such as
YouTube and IPTV, while energy consumption is a major
challenge in sustaining the applications.
• We propose a dynamic-backlight-scaling technology, develop
it as Android software, and discuss potential business models
to exercise the technology.
• We have released our software on the Hami Apps so that
people with Android phones can benefit from our technology.
• With the software installed, an HTC Desire mobile phone can save
18-31% backlight energy when browsing videos on YouTube. 9

10. We are the Research Center for IT Innovation
10